Regulator



Aug- 28, 1951 w. J. RADY ET AL 2,565,989

REGULATOR Original Filed Feb. l2, 1944 zal. :'o

Tamm

FORCE ARMA-rum: TnAvsL Patented Aug. 28, 1951 REGULATOR William J. Rady and Lyman A. Rice, Anderson, Ind., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Continuation of application Serial No. 522,0'i1, February 12, 1944. This application February 9, 1946, Serial No. 646,675

( Cl. 20L-51) 6 Claims. l

This invention relates to regulating devices which are provided to maintain the voltage of electric generators within certain limits and more particularly to the carbon pile type of regulator, which comprises a stack of carbon discs subject to spring pressure which is varied by an electromagnet which exerts a force in opposition to the spring pressure, the magnet being responsive to generator voltage and the force exerted thereby being variable in response to voltage variations.

It is well known that in a carbon pile regulator voltage regulation is effected by the variable resistance of the carbon pile due to the variable pressure exerted thereon. It is also well known that in order to exert the proper pressure on the pile, the force of the magnet which varies inversely as the square of the air gap must be counter balanced by a force which follows the same law of variation as the magnet pull and opposes the action of the magnet.

It has been attempted to provide this counter balancing force by providing a series of flat cantilever springs acting in opposition to the force of the magnet which progressively engage in greater numbers and at a shorter fulcrum on a. special seat and are designed to exert a force which increases at substantially the same rate as the pull of the magnet as the air gap decreases. This construction is not altogether satisfactory because of the fact that friction between the springs and between the springs and seat prevents accurate regulation.

It is the primary object of the present invention to provide, in a device of the character described, a spring means for controlling the pressure exerted on the carbon pile and opposing the force of the magnet which is so constructed and arranged that the force exerted thereby increases at the same rate as the force exerted by the magnet increases upon decrease in the air 88D.

It is a further object of the invention to provide spring means which is effective to exert a force in the manner set forth without modiiication by friction or other variable factors.

In the embodiment of the invention disclosed herein, these objects are accomplished by the provision of one or more semicircular springs which are elongated as the force exerted by the magnet increases, or by the provision of a corrugated diaphragm which is distorted upon increase of magnetic force, said springs and diaphragm being so arranged that the distortion of either is accomplished without frictional resistance thereto.

A further object is to provide a device of the character described which is simple in construction, durable and inexpensive.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a side elevation and diagrammatic representation of one type of structure embodying the present invention.

Fig. 2 shows in detail and in longitudinal section a device wherein the essence of this invention resides.

Fig. 3 is a view similar to Fig. 2 showing an alternate arrangement of details.

Fig. 4 is an end elevation of a spring structure in its normal state used in Figs. 1 and 2.

Fig. 5 yis a diagram illustrating the pull curve of the spring shown in Fig. 4.

Fig. 6 is a plan view of a part shown in section in Fig. 3.

Referring to Fig. 1, 20 represents a base upon which is mounted an electromagnet I5 including a U-shaped frame 2| having a core member 22 secured to the frame in any Well known manner. The core is surrounded by a coil indicated at 23. The arms of the frame are shown bent inwardly as at 24 so as to hold the coil in position. The base 20 supports standards 25 only one of which is shown. YThe standards support ball bearings 26 which receive pins 26a which serve as a practically frictionless pivot and support for a lever .or arm 2l.

As viewed in Fig. 1, one end of the lever 21 supports an armature 28, while the other end of the lever is provided with a projection 29 near the other end of the lever, said other end being connected with one end of a bowed spring 30.

The other end of the spring 30 is ilxed to the base 20 as at 3|, whereby the force of the spring is transmitted to the lever 21 tending to revolve it about its pivots 26a in a counterclockwise direction.

It is pointed out here that the spring 30 can be made of flat or round stock. The stiffness of the spring can be changed by changing the thickness of the material or the radius, and its rate of stili'- ness can also be changed by changing its sector angle. The projection 29 of the lever 21 bears against the face of a terminal plate 32, which engages the uppermost carbon disc of the pile 33. The pile of carbon discs 33 is compressed between arenoso the plate 32 and a terminal plate @t which is in sulated from the base 20 by an insulating washer 35.

Fig. 4 shows a bowed spring in its normal state of conguration. When the spring is anchored at its ends, the spring is deflected to increase its arc so as to storeinternal stresses whereby the spring exerts force to raise the armature and causes the boss or projection 29 to .bear against piate 02 to compress the carbon pile i3 between plates 32 and 34.

Fig. 5 represents the pull curve of the spnng means, the horizontal line @-M indicates the travel of the armature to close the air gap be-A tween the armature and the pole face while line O-N indicates the curve of the force of the spring means. In other words, the curve shown in Fig. 5 indicates the force of the spring which increases substantially in proportion to the increase in the magnetic force upon the armature as the air gap between the armature and the pole face decreases.

Fig. l illustrates also diagrammatically the use of this invention with an automotive generator. The diagram illustrates a generator o the shunt wound type having a brush 31| providing a. ground connection at :it and a brush from which a conductor 40 leads to a cut-out relay and thence to a battery 4i having a groundconnection 42. 'I'he electromagnet i5 is connected across the terminals of the generator by a lead 43. Also connected to the brush B is a eid winding 44 from which a conductor Mia maires the usual return ground connection which in this instance is accomplished through the variable resistanceA device, namely, the carbon pile 32|. The spring 30 acts upon the lever 2i tending to increase the compression of the carbon pile so as to lower its resistance and the electromagnet i acts upon the armature to pull the lever 2l in opposition to the force of spring 30.

The electromagnet i5 provided with the vcoil Eil which is connected across the terminals of the generator and hence, responsive to generator voltage, tends to decrease the compression of the carbon pile 33 and to increase its resistance as the generator voltage increases.

Referring to Fig. 2 an electromagnet t5 comprises a magnetizable tubular housing 00 to which is secured a plate 4'! in any suitable manner to provide an adequate iiux path for a relatively large magnetizable core 48 threadedly engaging the plate 41. The core 48 is provided with a slotu 49 so that it can be turned by a suitable tool to adjust the air gap between the core 4t and an armature 50. The core is held in the desired adjustedposition by screws si, passing through washers 52, overlying the lower end of the core 48 which has threaded engagement with the plate 41. The housing 46 encloses an actuating magnet coil 53 mounted upon a brass spool 55 supported by the core 48.

The upper end of the housing @t has an annular iiange provided with radial slots t@ to receive ears 62 of a plate 60 having an aperture to receive an extension 64 of the armature t0 and the plate 63 is fixed to the armature by rivets 63a.

A carbon pile housing 65 having radiating iins 66 is connected with the housing t@ at one end by screws 61. The screws pass through apertures, not shown, in the flange 00 of the housing 40 and extend through tubes B0, and through aperture 60 in a iiange l0 provided by the housing 65. When nuts 1| are threaded home upon the upper end of the screws 0l, the housings 46 and 00 are held in assembled relation.

A plate i5 is attached to the housing 65 by screw '16 and is insulated therefrom by an insuiating -plate it, insulating washer '|13 and insulating bushing le. The plate l5 is provided vwith a boss threadedly engaged by a screw 8| which engages a metal disc t2 to which a carbon disc 83 is attached for engagement with the upper end of a carbon pile t0. The screw 0| is turned to adjust initially the contact pressure between the carbon discs 0i located in a non-conducting tube f d0 of refractory material, such as porcelain.

The boss 64 of the armature engages a metal disc t0 to which a carbon disc t0 is attached for engagement with the lower end of the carbon pile 84. The boss 04 is held against the disc 0B by a plurality of springs Q0, similar in'. construction to spring 30. Each spring has one end anchored to one of the ears 62 and havx tively small.

Regulator of the type described ior Fig. 2 may be equally controlled by a corrugated diaphragm D00 having substantially the same eiect as a plurality of semi-circular springs 90. Fig. 3 shows a regulator using the corrugated diaphragm. The construction of the electromagnet and support of the electromagnet andthe carbon pile housing 65 and its associated parts are similar to those described for the construction shown in Fig. 2 and it will be suiiiciently understood from the marking of corresponding parts with the same reference characters. In Fig. 3 the only diierence in the main detail construction of parts are the housing 46', the armature assembly 50' and the diaphragm |00. In this instance the upper end of the housing 46 is formed with an annular recess 0| for the reception of the corrugated diaphragm |00 included in the armature assembly.

The amature assembly shown in Fig. 3 comprises the magnetizable armature 50', spacers H02, the diaphragm |00, spacers |03 and insulating discs |04, and these discs, diaphragm and spacers are secured to the armature by screws B05 and |06. Screws |06 secure to the armature a metal bracket i0'i which is insulated from the armature by the insulating disc |04. The bracket |07 is secured to a brass tube |00 engaging the metal disc 88 carrying the carbon disc 89 ior engagement with the lowermost carhon disc of the pile Bt.

The diaphragm |00 is punched out to form a series of spaced openings H0, and these portions of the diaphragm which lie between the openings and are numbered Hi, are corrugated in cross section, as shown in Figs. 3 and 6. This diaphragm constitutes a spring which vexerts a pressure on the carbon stack and is so formed vthat the force exerted thereby in opposition to the pull of the magnet increases at the same rate that the force of the magnet increases.

It is apparent that with the construction shown, as the springs 00 or the diaphragm |00 are distorted, as a result of movement of the magnet armature, there is no variation in frictional resistance to such distortion so that the accuracy of the rate of increase in the counter balancing force exerted by the springs or diaphragm is not interfered with or modified by friction in any way.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that otherforms might be adopted, all coming within the scope of the claims which follow.

This application is a continuation of Serial No. 522,071, filed February 12, 1944, now forfeited.

What is claimed is as follows:

l. A carbon pile regulator for controlling the field c urrent of a generator, comprising a stack of carbon discs through which current flows and means for varying the resistance of the carbon stack including an electromagnet having an armature movable in response to variations in generator voltage, an element connected therewith and engaging the carbon stack, spring means adapted to exert a normal pressure on the carbon stack and comprising a plurality of springs of semicircular form connected at one end to a single fixed base and at the other to a movable armature so as to urge the armature toward the carbon stack and oppose the movement of the armature in response to increase in generator voltage, said springs being so constructed that the force exerted thereby in opposition to movement of the armature increases at the same rate as the force of the magnet increases upon decrease in the air gap.

2. A carbon pile regulator for controlling the field current of a generator comprising a stack of carbon discs subjected to varying pressures, a member engaging one end of said stack and adapted to be set in fixed position relative thereto, an electromagnet having an armature assembly movable in response to variations in generator voltage for reducing the pressure on said discs as the voltage increases, and including means for engaging the other end of the carbon stack, a plurality of bowed springs having one end secured to the fixed member and the other end secured to the armature assembly so as to exert an initial pressure upon the carbon stack and oppose movement of the armature in response to increase in generator voltage, said springs being deformed by movement of the armature thereby creating a force in opposition to its movement which increases at the same rate as the force exerted by the magnet increases upon decrease of its air gap.

3. AV carbon pile regulator for controlling the ileld current of al generator comprising a stack of carbon discs subjected to varying pressures, an adjustable member engaging one end of said stack and adapted to be set in any desired position relative to said stack to determine the initial pressure thereon, an electromagnet having 'an amature assembly movable in response to variations in generator voltage for reducing the pressure on said discs as the voltage increases and including means for engaging the other end of the carbon stack, a plurality of bowed springs' having one end secured to the ilxed member and the other end secured to the amature assembly so as to exert an initial pressure upon the carbon stack and oppose movement of the armature in response to increase in generator voltage.' said springs being deformed by movement of the armature, thereby creating a force in opposition to its movement which increases at the same rate n 6 as the force exerted by the magnet increases upon decrease of its air gap.

4. In a carbon pile apparatus, the combination with a stack of carbon discs, of a housing for enclosing the stack, an electromagnet including a frame having means for supporting the housing, said housing including a part forming an abutment for one end of the stack, an armature assembly including a part forming an abutment for the other end of the stack and having radial arms extending therefrom, and resilient means for holding the armature assembly in spaced relation to the electromagnet, said resilient means including a plurality of bowed spring wires each wire having one end xed to the housing and the other end fixed to one of the arms respectively, said wires being placed under initial tension for moving the armature away from the electromagnet to compress the stack, said bowed wires increasing their tension in proportion to the movement of the armature assembly toward the electromagnet.

5. In a carbon pile apparatus the combination with a carbon pile, of a, housing enclosing the pile and having radial arms extending outwardly therefrom, an electromagnet including a frame having standards extending upwardly therefrom for supporting the housing, a terminal insulatingly supported by the housing, said terminal engaging one end of the pile, an armature assembly including a part for engaging the other end of the pile and having radial arms extending therefrom, and resilient means for suspending the armature assembly in spaced relation to the electromagnet, said resilient means including a plurality of bowed spring members each spring member having one end -anchored to one of the arms of the housing and the other end to one arm of the armature assembly, said spring members when anchored being placed under an initial tension for moving the armature in a direction causing the part to compress the pile and urging the armature away from the electromagnet.

6. In a carbon pile Iapparatus the combination with a carbon pile, of a housing enclosing the pile,

an electromagnet including a frame having arms extending therefrom for supporting the housing relative to the frame, a conducting part insulatingly supported by the housing and operating as an abutment for one end of the pile, an armature assembly including a corrugated diaphragm and a conducting part for engaging the other end of the pile, said diaphragm having a peripheral flange fixed to the frame so the corrugations therein are placed under an initial tension for moving the armature assembly in a direction to compress the pile and urging the armature assembly away from the electromagnet.

WILLIAM J. RADY. LYMAN A. RICE.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,159,674 Honold Nov. 9, 1915 2,332,140 Finnegan Oct. 19, 1943 2,394,753 Crotch i Feb. 12, 1946 FOREIGN PATENTS Number Country Date 705,669 France Mar. 16, 1931 

